The present invention relates to high voltage phasing tools in general and to long range wireless phasing tools in particular.
Three phase high voltage distribution and transmission systems consist of three energized conductors and a fourth neutral or ground conductor. The three energized conductors are referred to as phases and generally labeled as A, B, C or 1, 2, 3 or something similar depending on the utility. These three phases are electrically displaced by 120 degrees. In the simplest arrangement, the first phase or reference phase is considered 0 degrees, the next phase is displaced 120 degrees from the first and the last phase is displaced 240 degrees from the first.
Referring to FIG. 1, a table is provided showing the six possible ways to attach any three conductors having three phases of 0 degrees, 120 degrees, and 240 degrees. Each of these six different connections may or may not have a different outcome depending on the device(s) being powered and may or may not be considered correct for the situation. The direction of rotation of a three phase motor is determined by the placement of the three phase connections. Improper connections on a three phase motor may have disastrous effects on the results such as machinery running backwards in a manufacturing plant. Incorrectly wired three phase transformer banks, consisting of three individual transformers can produce any number of odd phase angles between 0 and 360 degrees in 30 degree steps
Individual phase identification may get lost in large industrial complexes which now may exceed millions of square feet. The individual phase conductors may travel through numerous junction boxes and hundreds or thousands of feet in conduit undergoing multiple color and wire type changes as large plants expand over the decades.
Individual conductor phase identification may get lost in improperly marked underground electrical systems which now may travel for many miles underground. New construction of underground systems will require initial phase identification and verification. Mapping and phase tagging and systematic verification of system records, new and old, require phase identification. Unauthorized digging or trenching up of an underground electrical system is not uncommon resulting in loss of phase identification. Natural disasters such as earthquakes, floods, etc. may also result in loss of underground phase identification.
Individual phase identification may get lost in overhead distribution and transmission systems as well. These lines are also subject to the natural disasters mentioned above as well as hurricanes, tornadoes, forest fires, wind, snow and ice storms. Man made destruction of electric utility systems from automobiles, airplanes, trains, terrorist, war, etc. may also result in loss of phase identification.
U.S. Pat. No. 6,642,700, the disclosure of which is incorporated herein by reference, uses a full duplex communications system, such as cell phones and precision timing sources to simultaneously time tag the zero crossing or other significant features of a voltage from the electric utility grid. It has massive data storage and processing capability correlating zero crossing data until it locates similar time tags and computes phase angles based on the time difference in the time tags at the reference and field locations.
U.S. Pat. No. 7,109,699, the disclosure of which is incorporated herein by reference, also uses a full duplex communications system and multiple radio frequency translators in the communications link between the reference and field locations.
There is therefore a need for a wireless high voltage phasing tool that is accurate, easy to use and read and can be used when the high voltage distribution or transmission lines are separated by some distance.